Out-patients of a single radiology center are included in this retrospective analysis. All patients are referred to an ambulant CCTA. All scans are performed with a Siemens Somatom Sensation Cardiac 64 Computer Tomograph and analyzed with Siemens Syngo Plaza software. Patients with an initial heart rate of ≥ 75 bpm are either pretreated with bisoprolol 10mg p.o. alone (group 1) or a combination of bisoprolol 10mg and ivabradine 7.5mg p.o. (group 2) one hour before the CT scan.